1. Field of the Invention
The present invention relates to a cross flow fan provided as a blowing means for such as an air conditioner.
2. Related Art
FIGS. 18 to 22 are diagrams illustrating examples of air conditioners in which cross flow fans 8 are mounted. FIG. 18 is a perspective view of a main body 1 of an air conditioner in which an upper air inlet grille 5 is not disposed on the rear surface side of a round starting point F.sub.0 of a scroll casing 10, and FIG. 19 is a cross-sectional view, taken along a plane X in the direction of arrow L, of the main body 1 of the air conditioner in FIG. 18. FIG. 20 is a perspective view of the main body 1 of the air conditioner in which the upper air inlet grille 5 is disposed on the rear surface side of the round starting point F.sub.0 of the scroll casing 10, and FIG. 21 is a cross-sectional view, taken along the plane X in the direction of arrow L, of the main body 1 of the air conditioner in FIG. 20. FIG. 22 is a diagram illustrating the flow of air in FIG. 21.
In FIG. 18, the main body 1 of the air conditioner forms a casing which is comprised of a housing 2, which is located on the rear surface side of main body 1 of the air conditioner, as well as a panel 3 having a rotatable openable and detachable front air inlet grille 4 and the upper air inlet grille 5. Further, an air outlet 6 is formed by the housing 2 and the panel 3.
In FIG. 19, reference numeral 7 denotes a heat exchanger which is bent in a chevron shape which is disposed on the front surface side of main body 1 of the air conditioner with respect to the round starting point F.sub.0, which is a starting point of the scroll casing 10. Numeral 19 denotes a drain pan for receiving drain water produced an air is condensed by the heat exchanger 7. Numeral 17 denotes a dust removing filter for removing dust in the air sucked into the main body 1 of the air conditioner. Numeral 18 denotes an air cleaning filter for cleaning air by means of activated carbon.
A section of the housing 2 which extends from its portion close to the rear surface portion to its lower portion is formed by the scroll casing 10 and an air-outlet lower guide 12 continuing and extending from the scroll casing 10. A none section is formed by the drain pan 19, a stabilizer 11, and an air-outlet upper guide 13. An outlet duct 14 is a portion surrounded by the air-outlet upper guide 13, the air-outlet lower guide 12, and the panel 3, and is a portion for guiding the air flow from the cross flow fan 8 into the air outlet 6. The cross flow fan 8 is formed by an impeller 9, the scroll casing 10, and the outlet duct 14.
In the main body 1 of the air conditioner thus constructed, as the impeller 9 of the cross flow fan 8 rotates about the center O of the rotating shaft of the impeller in the direction of arrow A as shown in FIG. 19, a circulating vortex 21 in induced and produced, and the impeller 9 sucks air and starts blowing the air. As a result, air is sucked from the front air inlet grille 4 and the upper air inlet grille 5. Then, as indicated by arrow B, after the air passes through the dust removing filter 17 and part of the air passes through the air cleaning filter 16, the air is subjected to heat exchange by the heat exchanger 7, and is sucked into the impeller 9 of the cross flow fan 8. Subsequently, the air C blown out from the impeller 9 of the cross flow fan 8 is collected directly or by the scroll casing 10, and passes through the outlet duct 14. After the blowing direction is regulated appropriately by a left/right blowing-direction changing plate 16 and up/down blowing-direction changing plates 15, the air is then supplied from the air outlet 6 to a room 22 to air-condition the room 22.
FIGS. 20 and 21 are diagrams illustrating an example of the air conditioner in which, in contrast to the above-described air conditioner, the area of the heat exchanger 7 is increased, and the upper air inlet grille 5 in disposed also on the rear surface side of the round starting point P.sub.0 so as to attain high performance of the air conditioner. The operation is similar to that of the air conditioner shown in FIG. 19.
With the air conditioner having the above-described cross flow fan 8, when the air in blown out from the impeller 9 of the cross flow fan 8, since the upper air inlet grille 5 is disposed also on the rear surface side of the round starting point F.sub.0 of the scroll casing 10 the blown-out air flow C impinges upon the scroll casing 10 in the vicinity of the impeller 9, and pressure fluctuation P occurs in this portion. Consequently, the phenomenon takes place in which noise is aggravated an the vanes of the impeller 9 pass through the section of the pressure fluctuation P, and this phenomenon has been a problem.